Maintain command consistency

To maintain command consistency, use command "iw dev [interface]
set txpower auto/limit/fixed [transmit power (mBm)]" to set the
transmit power.
Since using the above command results in the 'wdev' parameter NULL,
a new function 'wiphy_get_vwifi_vif' was added to obtain the virtual
interface.
Additionally, the 'type' parameter is used to distinguish between
"auto/limit/fixed" :
auto: Use default transmit power
limit: Restrict power limits to a specific value
fixed: Set power freely

Author: jychen0611

scripts/verify.sh

@@ -24,10 +24,10 @@ if [ $final_ret -eq 0 ]; then
     # to avoid device or resource busy error
     sleep 0.5
 
-    # set transmit power
-    sudo iwconfig vw0 txpower 11
-    sudo iwconfig vw1 txpower 12
-    sudo iwconfig vw2 txpower 13
+    # set transmit power (mBm)
+    sudo iw dev vw0 set txpower auto
+    sudo iw dev vw1 set txpower fixed 1200
+    sudo iw dev vw2 set txpower fixed 1300
 
     # get phy number of each interface
     sudo iw dev > device.log

vwifi.c

@@ -1843,18 +1843,63 @@ static int vwifi_delete_interface(struct vwifi_vif *vif)
     return 0;
 }
 
+static struct vwifi_vif *wiphy_get_vwifi_vif(struct wiphy *wiphy)
+{
+    struct wireless_dev *wdev;
+    struct vwifi_vif *vif = NULL;
+
+    list_for_each_entry (wdev, &wiphy->wdev_list, list) {
+        vif = container_of(wdev, struct vwifi_vif, wdev);
+        break; /* Assuming only one virtual interface is present */
+    }
+
+    return vif;
+}
+
 /* Set transmit power for the virtual interface */
 static int vwifi_set_tx_power(struct wiphy *wiphy,
                               struct wireless_dev *wdev,
                               enum nl80211_tx_power_setting type,
                               int mbm)
 {
-    struct vwifi_vif *vif = wdev_get_vwifi_vif(wdev);
+    struct vwifi_vif *vif = wiphy_get_vwifi_vif(wiphy);
+    /* Validate vif pointer */
+    if (!vif) {
+        pr_info("vwifi_vif is NULL\n");
+        return -EINVAL;
+    }
+
     if (mutex_lock_interruptible(&vif->lock))
         return -ERESTARTSYS;
-    /* 1 dBm = 100 mBm */
-    vif->tx_power = MBM_TO_DBM(mbm);
+
+    int power = MBM_TO_DBM(mbm);
+    switch (type) {
+    case NL80211_TX_POWER_AUTOMATIC:
+        /* Use default transmit power (11 dBm) */
+        vif->tx_power = 11;
+        break;
+
+    case NL80211_TX_POWER_LIMITED:
+        /* Restrict power limits to a specific value (0 ~ 18 dBm) */
+        if (power < 0)
+            vif->tx_power = 0;
+        else if (power > 18)
+            vif->tx_power = 18;
+        else
+            vif->tx_power = power;
+        break;
+
+    case NL80211_TX_POWER_FIXED:
+        /* Set power freely */
+        vif->tx_power = power;
+        break;
+
+    default:
+        return -EINVAL; /* Invalid parameter */
+    }
+
     mutex_unlock(&vif->lock);
+
     return 0;
 }
 
@@ -1864,6 +1909,11 @@ static int vwifi_get_tx_power(struct wiphy *wiphy,
                               int *dbm)
 {
     struct vwifi_vif *vif = wdev_get_vwifi_vif(wdev);
+    /* Validate vif pointer */
+    if (!vif) {
+        pr_info("vwifi_vif is NULL\n");
+        return -EINVAL;
+    }
     *dbm = vif->tx_power;
     return 0;
 }